Put the milk for the polenta in a saucepan along with 400ml water. Add the bay leaf, onion, and thyme if using. Bring to a near-boil, then take off the heat and set aside to infuse for 20 minutes.

Strip the spring greens or kale leaves away from their stalks. Roll the leaves up and slice across them to produce thick ribbons. Steam them for about 3 minutes, or simmer in salted water for just 2 minutes, until tender, then drain well. Squeeze or press the greens in the colander to remove as much water as you can. Toss with the knob of butter and some salt and pepper and keep warm.

For the polenta, strain the infused milk and water into a clean pan. Bring to a simmer, then stir in the polenta in a thin stream until the mixture is smooth. Return to a simmer for just 1 minute, then remove from the heat. Stir in the butter and season generously with salt.

Scoop the soft polenta into warm bowls. If it starts thickening, loosen it with a splash of hot water. Top with the cheese and put a heap of buttered greens alongside. Grind over some pepper and serve.